Measuring the environmental dimensions of human migration: The demographer's toolkit

In recent years, the empirical literature linking environmental factors and human migration has grown rapidly and gained increasing visibility among scholars and the policy community. Still, this body of research uses a wide range of methodological approaches for assessing environment–migration relationships. Without comparable data and measures across a range of contexts, it is impossible to make generalizations that would facilitate the development of future migration scenarios. Demographic researchers have a large methodological toolkit for measuring migration as well as modeling its drivers. This toolkit includes population censuses, household surveys, survival analysis and multi-level modeling. This paper's purpose is to introduce climate change researchers to demographic data and methods and to review exemplary studies of the environmental dimensions of human migration. Our intention is to foster interdisciplinary understanding and scholarship, and to promote high quality research on environment and migration that will lead toward broader knowledge of this association.     

在气候影响研究中引入随机天气发生器的方法和不确定性

通过采用不同的随机天气发生器生成一定气候背景下各种气候变率情景，许多学者在最近的研究中已经认识到气候变率对农作物生长发育影响的重要性。传统的气候影响评估方法直接以大气环流模式的模拟试验结果作为未来气候情景，这样不可能理解如上的重要性。本文着重评述将随机天气发生器应用于气候变化影响研究的一般方法框架，以及作者的具体个例研究方法。文中最后分析了目前该领域研究中还存在的一些不确定性。 在当前的气候变化影响研究中，有不同的方法用来研制一种称为WGEN的典型随机天气发生器的参数化方案及其随机试验方法。不同的研究者也有不同的参数调控方法。通常的思路是通过气候控制试验和2×CO2试验之间的气候变量平均值和方差的变化来扰动随机天气发生器的参数，以生成未来逐日气候变化情景。本文作者根据短期气候预测模式的输出产品建立了一套WGEN的参数化方案及其随机试验方法，并且在时间和空间两个尺度上检验和评估了此参数化方案下WGEN的模拟能力。另外，作者由未来降水的变化，调试随机天气发生器参数，生成了气候变率变化情景。这些参数调节可以产生各种不同类型和定性大小的气候变率变化，用于气候影响评估的敏感性分析。通过如上方法，作为一个个例，文中评估了未来气候变率变化     

Unveiling hidden migration and mobility patterns in climate stressed regions: A longitudinal study of six million anonymous mobile phone users in Bangladesh

Climate change is likely to drive migration from environmentally stressed areas. However quantifying short and long-term movements across large areas is challenging due to difficulties in the collection of highly spatially and temporally resolved human mobility data. In this study we use two datasets of individual mobility trajectories from six million de-identified mobile phone users in Bangladesh over three months and two years respectively. Using data collected during Cyclone Mahasen, which struck Bangladesh in May 2013, we show first how analyses based on mobile network data can describe important short-term features (hours–weeks) of human mobility during and after extreme weather events, which are extremely hard to quantify using standard survey based research. We then demonstrate how mobile data for the first time allow us to study the relationship between fundamental parameters of migration patterns on a national scale. We concurrently quantify incidence, direction, duration and seasonality of migration episodes in Bangladesh. While we show that changes in the incidence of migration episodes are highly correlated with changes in the duration of migration episodes, the correlation between in- and out-migration between areas is unexpectedly weak. The methodological framework described here provides an important addition to current methods in studies of human migration and climate change.     

Operationalizing longitudinal approaches to climate change vulnerability assessment

The past decade has seen a proliferation of community-scale climate change vulnerability assessments globally. Much of this work has employed frameworks informed by scholarship in the vulnerability field, which draws upon interviews with community members to identify and characterize climatic risks and adaptive responses. This scholarship has developed a baseline understanding of vulnerability in specific places and industries at particular times. However, given the dynamic nature of vulnerability new methodologies are needed to generate insights on how climate change is experienced and responded to over time. Longitudinal approaches have long been used in sociology and the health sciences to capture the dynamism of human processes, but their penetration into vulnerability research has been limited. In this article, we describe the application of two longitudinal approaches, cohort and trend studies, in climate change vulnerability assessment by analyzing three case studies from the Arctic where the authors applied these approaches. These case studies highlight how longitudinal approaches can be operationalized to capture the dynamism of vulnerability by identifying climate anomalies and trends, and how adaptations develop over time, including insights on themes such as social learning and adaptive pathways.     

How qualitative approaches matter in climate and ocean change research: Uncovering contradictions about climate concern

There is growing acknowledgement of the need for both quantitative and qualitative methods to unravel complex human-environment interactions and inform a more advanced move towards global sustainability. Nonetheless, qualitative methods still play an understated role in climate and ocean change research. One important reason for this are continuing tendencies in the natural sciences to value ‘hard’ and value-free quantitative approaches over ‘soft’ and value-laden qualitative approaches. This paper argues that to overcome such methodological reservations, it is necessary to inform not only about the key characteristics of qualitative research but also – and this has received little attention – about the concrete empirical insights that can be gained from qualitative as opposed to quantitative data, despite sharing the same research focus.The environmental literature still lacks relevant examples from fieldwork that explain in detail how exactly decisive information is elicited from specific qualitative datasets, thereby illustrating how qualitative approaches matter. This paper seeks to help fill this gap by demonstrating to sceptical quantitative researchers the necessity and added value of integrating qualitative data in global environmental change research and highlighting impeding factors. This is done by presenting empirical findings about climate and ocean change adaptation in Norwegian coastal fisheries and elucidating how different qualitative interview techniques reveal that fishers who initially state that they do not worry about climate change actually do worry, and vice versa. Self-categorisation theory from social psychology is used to better explain such contradictory statements. Detecting salient but masked climate concern and understanding the reasons behind it are crucial for avoiding misleading conclusions and effectively tailoring adaptation strategies to the requirements of specific audiences.     

Climate-Induced migration and unemployment in middle-income Africa

One of the major unresolved questions in the study of vulnerability to climate change is how human migration will respond in low and middle-income countries. The present study directly addresses this lacuna by using census data on migration from 4 million individuals from three middle-income African countries over a 22-year period. We link these individuals to climate exposures in their origins and estimate climatic effects on migration using a fixed-effects regression model. We show that climate anomalies affect mobility in all three countries. Specifically, mobility declines by 19% with a 1-standard deviation increase in temperature in Botswana. Equivalent changes in precipitation cause declines in migration in Botswana (11%) and Kenya (10%), and increases in migration in Zambia (24%). The mechanisms underlying these effects appear to differ by country. Negative associations between precipitation anomalies, unemployment, and inactivity suggest migration declines may be due to an increased local demand for workers to offset production risk, while migration increases may be indicative of new opportunities in destinations. These country-specific findings highlight the contextually-specific nature of climate-migration relationships, and do not support claims that climate change is widely contributing to urbanization across Africa.     

Agriculture,irrigation and drought induced international migration: Evidence from Mexico

There is now substantial empirical evidence that climatic variability increases international migration, but relatively little is known about the mechanism driving the association and about adaptations that may reduce it. We use detailed data on migrants from Mexico to the U.S. to provide evidence in support of the hypothesis that drought induced migration from Mexico to the U.S. is mediated by agricultural income shocks. Migration rates increase in drought years, but only in Mexico’s drier regions, and the response is stronger in states and seasons in which agricultural production is also more sensitive to precipitation. Moreover, among the sample, only farmers display a significant increase in migration rates in drought years, and the effect is substantially weaker for households with access to irrigation.     

Asking about climate change: Reflections on methodology in qualitative climate change research published in Global Environmental Change since 2000

There is increasing evidence that climate change will strongly affect people across the globe. Likely impacts of and adaptations to climate change are drawing the attention of researchers from many disciplines. In adaptation research focus is often on perceptions of climate change and on vulnerability and adaptation strategies in a particular region or community. But how do we research the ways in which people experience changing climatic conditions, the processes of decision-making, the actual adaptation strategies carried out and the consequences of these for actors living and dealing with climate change? On the basis of a literature review of all articles published in Global Environmental Change between 2000 and 2012 that deal with human dimensions of climate change using qualitative methods this paper provides some answers but also raises some concerns. The period and length of fieldwork and the number and types of interviews conducted are, for example, not always clear. Information on crucial aspects of qualitative research like researcher positionality, social positions of key informants, the use of field assistants, language issues and post-fieldwork treatment of data is also lacking in many articles. We argue that this lack of methodological information and reflections is particularly problematic in an interdisciplinary field such as climate change research and journals such as Global Environmental Change and that clearer communication is key to facilitate truly interdisciplinary dialogue.     

Climate variability and inter-provincial migration in South America, 1970–2011

We examine the effect of climate variability on human migration in South America. Our analyses draw on over 21 million observations of adults aged 15–40 from 25 censuses conducted in eight South American countries. Addressing limitations associated with methodological diversity among prior studies, we apply a common analytic approach and uniform definitions of migration and climate across all countries. We estimate the effects of climate variability on migration overall and also investigate heterogeneity across sex, age, and socioeconomic groups, across countries, and across historical climate conditions. We also disaggregate migration by the rural/urban status of destination. We find that exposure to monthly temperature shocks has the most consistent effects on migration relative to monthly rainfall shocks and gradual changes in climate over multi-year periods. We also find evidence of heterogeneity across demographic groups and countries. Analyses that disaggregate migration by the rural/urban status of destination suggest that much of the climate-related migration is directed toward urban areas. Overall, our results underscore the complexity of environment-migration linkages and challenge simplistic narratives that envision a linear and monolithic migratory response to changing climates.     

Studying local climate adaptation: A heuristic research framework for comparative policy analysis

Climate change poses a significant risk for communities, and local governments around the world have begun responding by developing climate adaptation policies. Scholarship on local adaptation policy has proliferated in recent years, but insufficient attention has been paid to operationalization of the unit of analysis, and methods employed are typically inadequate to draw inferences about variation across cases. This article seeks to contribute to the conceptual and methodological foundations of a research agenda for comparative analysis of local adaptation policies and policy-making. Synthesizing insights from policy studies literature and existing adaptation research, the article identifies and operationalizes two aspects of public policy—policy content and policy process—which are salient objects of comparative analysis that typically vary from one community to another. The article also addresses research design, outlining a comparative case study methodology that incorporates various qualitative analytical techniques as the vehicle to examine these policy elements in empirical settings.     

Is anticipatory governance opening up or closing down future possibilities? Findings from diverse contexts in the Global South

There is an urgent need to understand how anticipation processes such as scenario planning impact governance choices in the present. However, little empirical research has been done to analyze how anticipation processes frame possibilities for action. This paper investigates how assumptions about the future open up or close down anticipatory governance actions in a large number of climate-focused anticipation processes. We focused on four Global South regions: West Africa, South Asia, Southeast Asia and Central America. We apply an analytical framework that identifies four diverse approaches to anticipatory governance and connect this to the notion of opening up or closing down of possibility spaces for action. Across the four regions, we find that many anticipation processes open up dialogue about deep uncertainties and pluralistic worldviews but end up informing mostly technocratic and linear planning actions in the present. We also observe that anticipation processes in the Central American context more often break this trend, particularly when transformative ambitions are formulated. The focus on more technocratic futures and linear planning strategies and reliance on a mostly North-based global futures industry may close down more culturally, socially and politically diverse and regionally relevant future worldviews in anticipation processes.     

Modelling complex systems of heterogeneous agents to better design sustainability transitions policy

This article proposes a fundamental methodological shift in the modelling of policy interventions for sustainability transitions in order to account for complexity (e.g. self-reinforcing mechanisms, such as technology lock-ins, arising from multi-agent interactions) and agent heterogeneity (e.g. differences in consumer and investment behaviour arising from income stratification). We first characterise the uncertainty faced by climate policy-makers and its implications for investment decision-makers. We then identify five shortcomings in the equilibrium and optimisation-based approaches most frequently used to inform sustainability policy: (i) their normative, optimisation-based nature, (ii) their unrealistic reliance on the full-rationality of agents, (iii) their inability to account for mutual influences among agents (multi-agent interactions) and capture related self-reinforcing (positive feedback) processes, (iv) their inability to represent multiple solutions and path-dependency, and (v) their inability to properly account for agent heterogeneity. The aim of this article is to introduce an alternative modelling approach based on complexity dynamics and agent heterogeneity, and explore its use in four key areas of sustainability policy, namely (1) technology adoption and diffusion, (2) macroeconomic impacts of low-carbon policies, (3) interactions between the socio-economic system and the natural environment, and (4) the anticipation of policy outcomes. The practical relevance of the proposed methodology is subsequently discussed by reference to four specific applications relating to each of the above areas: the diffusion of transport technology, the impact of low-carbon investment on income and employment, the management of cascading uncertainties, and the cross-sectoral impact of biofuels policies. In conclusion, the article calls for a fundamental methodological shift aligning the modelling of the socio-economic system with that of the climatic system, for a combined and realistic understanding of the impact of sustainability policies.     

Understanding the relationship between environmental change and migration: The development of an effects framework based on the case of northern Ethiopia

Empirical work on the relationship between environmental stress and human migration has blossomed over the last 10 years. While such work has provided important insights into this relationship, there has been, to date, limited effort expended on generating a generalisable framework for apprehending such interactions. This paper seeks to address this deficit. Based on semi-structured interviews in two sending and four receiving areas in northern Ethiopia, it explores dominant mobility narratives among populations whose livelihoods are exposed to a range of environmental stresses. Analysis of these narratives corroborates findings from other empirical studies on the subject, highlighting how the impact of environmental stress on human mobility can only be understood within the context in which it occurs. To this end the paper attempts to generate a typology of interactions between environmental and non-environmental factors shaping mobility. The typology is based on four effects: additive, enabling, vulnerability and barrier effects. It is thought to provide a generalisable conceptual language which is capable of describing the role of environmental stress in mobility decisions and thereby offering a systematic means for thinking through the processes by which environmental stress impacts upon mobility. While the framework is hypothesised to be suitably generalisable to account for other contexts and other environmental stresses, this still needs to be tested. In addition it is acknowledged that the framework suffers from some major limitations. Most notable is reliance on a conceptually false distinction between environmental and non-environmental factors, and the inability to account for the non-environmental features which shape perceptions of migration.     

Economic drivers of migration and climate change in LDCs

Environmental migration is a topic which has given rise to widespread debate and gloomy predictions about the state of the world in 2050, but where rigorous research and empirical evidence are unfortunately in short supply. In this paper, we review the existing research on and empirical evidence of how climate change and climate variability in Less Developed Countries (LDCs) affects two main drivers of migration identified by migration models in the economic literature, namely income level differentials between origin and destination areas and income variability in origin areas, and how they in turn affect migration. We find that there are serious gaps in both the economic and the environmental literature that render it impossible to make sound and robust predictions of how climate change and increased climate variability will affect the economic migration drivers, and of how these in turn may change existing migration patterns. There are some empirical indications that income differentials may increase due to lower income levels in the origin areas of LDCs, but virtually no evidence exists of the effects of climate change or increased climate variability on income variability. Furthermore, although a negative relationship between migration and rainfall has been established by many researchers, there is only very limited evidence as to what drives it. A clearer picture of the driving force behind the link between rainfall and migration would greatly benefit policymaking in this area.     

气候变化情景生成技术研究综述

简单回顾了气候变化对农业生产影响研究的进展,分析了气候变化情景生成技术研究的必要性,即影响模式与ＧＣＭｓ的嵌套困难及对气候变率和产量变率的认识。指出该技术是目前这一领域研究的关键所在。     

Situated adaptation: Tackling the production of vulnerability through transformative action in Sri Lanka’s Dry Zone

Drawing attention to the production of vulnerability across scales in Sri Lanka, we contribute to knowledge of why certain people and social groups are vulnerable. We build our contribution on the theoretical application of ‘situated adaptation’. A situated analytical approach identifies, assesses, and responds to the everyday realities and politics of those living in climate changed environments. It highlights uneven geographies of vulnerability and opportunity, while identifying new imaginations and possibilities for transformative action that counter the production of vulnerability. We illustrate the utility of ‘situated adaptation’ by filling an empirical gap relating to experiences of political-economic and environmental change in Sri Lanka’s Dry Zone. We detail situated experiences by drawing on field research in the Anuradhapura District, revealing how the lives and livelihoods of farmer participants are structured by a productivity-vulnerability paradox. We demonstrate how a prevalent adaptation-development paradigm (whereby development and adaptation programs co-exist in theory and practice) is unable to address the structural drivers of vulnerability in Sri Lanka’s Dry Zone. A situated adaptation approach both explains why this is the case and highlights opportunities for alternative transformative actions, potentially identifying a more democratic and egalitarian politics of co-determining socionatural change.     

Linking internal and external transformation for sustainability and climate action: Towards a new research and policy agenda

Climate change is an increasing threat to sustainable development worldwide. However, the dominant incremental policy approaches have not generated action at anywhere near the rate, scale or depth that is needed. This is largely due to the fact that climate change has historically been framed as a purely external, technical challenge. There is an urgent need for a more integral understanding that links internal and external (collective and systems) approaches to support transformation. However, related knowledge is scarce and fragmented across disciplines. This study addresses this gap. Through a systematic literature review, we analyse how the linkages between internal and external change are portrayed and understood in current research. We assess the scope, perspectives and approaches used to understand why, and how, internal change relates to climate action and sustainability. Our results highlight patterns and gaps regarding foci, conceptualisation, methods, epistemology, ontology and ethics that hamper emergent solutions and progress. Starting from the status quo, we propose an integrated model of change as an agenda and roadmap for future research, policy and practice.     

Adapting science to a warming world

Climate change is complicating the variables that Alaskans consider when planning for the future. Communities, agencies and other entities have begun to grapple with both the information that they need to adapt to a changing climate and how the processes and practices of science should change to make science more useful. We reviewed sixty-three documents that expressed practical research needs related to climate change in Alaska. Documents nearly unanimously expressed that science, as it is currently practiced, is inadequate to meet the challenges of climate change. They call for processes that are more transparent, collaborative, and accessible. They recommend changed practices including maintaining accessible data-sharing archives, building networks for knowledge sharing, and creating place-based long-term partnerships with communities. They advocate integrating local knowledge, but infrequently address the complexities of how this is best accomplished. They also suggest the need for improved training in interdisciplinary research and changes in the incentive structure of research institutions. This review complements the climate-change literature by providing concrete suggestions about how to increase the utility of science from a region that is experiencing some of the most dramatic climatic change on the planet.     

气候变化与气候层次结构初探

应用相空间经验正交展开方法，分析了四川降水、温度局地气候变化的主要特征及与其层次结构的关系。结果表明：气候作为一个多层次复杂系统，其变化表现出明显的层次结构特征，气候突变多反映在较高层次结构上，非突变变化多属于较低层次结构；高层次决定了气候变化的基本形态，低层次存在反馈作用；正（负）反馈作用可加强（减弱）气候变化的突变性；气候突变的强度和时问具有一定的层次结构差异性。     

Many roads to Paris: Explaining urban climate action in 885 European cities

Research on urban climate action has identified a broad range of potential factors explaining why and how local governments decide to tackle climate change. However, empirical evidence linking such factors in order to explain actual urban climate action has so far been mixed. To address this roadblock, our paper relies on a novel approach, postulating that different configurations of factors may lead to the same outcome (“equifinality”), through a qualitative comparative analysis (QCA). It is based on an available data set of local climate mitigation plans in 885 European cities. We find that urban climate action is systematically associated with four qualitatively different configurations of factors, each with its own consistent narrative (“networker cities”, “green cities”, “lighthouse cities”, “fundraising cities”). Crucially, some factors play a positive role in some configurations, a negative in others, and no role in further configurations (e.g., whether a city is located in a country with supportive national climate policies). This confirms that there is no single explanation for urban climate action. Achieving greater robustness in empirical research about urban climate action may thus require a shift, both conceptual and methodological, to the interactions between factors, allowing for different explanations in different contexts.